Flying on the step?

I'm reading "Fate is the Hunter" and just read something interesting. Gann
states that they would climb to 100 feet above their cruising altitude and
then descend the 100 feet back down. He called this "flying on the step."
He claims that it bought them a few more knots of airspeed.

Has anyone heard of this? Is it normal practice? Or is it one of those
practices that have been disproven?

Personally, I've never heard of this practice.

" wrote in message
hlink.net...
I'm reading "Fate is the Hunter" and just read something interesting.
Gann
states that they would climb to 100 feet above their cruising altitude and
then descend the 100 feet back down. He called this "flying on the step."
He claims that it bought them a few more knots of airspeed.

Has anyone heard of this? Is it normal practice? Or is it one of those
practices that have been disproven?

You might as well have asked about "low wing or high wing".

Many people, including those who otherwise have great heads on their
shoulders, will swear up and down that "flying on the step" is a real and
useful practice. Many others will just as vehemently point out that there's
no aerodynamic basis for the claim, and that basic physics argues against
it.

Peter Garrison wrote a decent article on the topic several years back, and
it's come up here every now and then over the years as well. Google Groups
can help fill you in on past discussions.

Bottom line: if there were really something to it, it would be wide-spread
industry and military practice. And yet, all those folks continue to climb
to their altitude, accelerate to cruise speed and then throttle back to
maintain that speed.

I will say this (yeah, I know I already wrote my "bottom line" )...it's a
great question if for no other reason than it gets people thinking about
what the proper sequence of events for climbing and cruising are, as well
the the whys and wherefors regarding an airplane's speed versus power
relationship.

Pete

On Sun, 31 Oct 2004 14:05:51 -0800, "Peter Duniho"
wrote:

Bottom line: if there were really something to it, it would be wide-spread
industry and military practice. And yet, all those folks continue to climb
to their altitude, accelerate to cruise speed and then throttle back to
maintain that speed.

Perhaps there is something to it then, check out this blurb from a 747
discussion group, the subject for this discussion was started by
someone asking about flying on the step:

***Begin quote***
As for flying 'on the step', I believe Jetguy's on the money. For a
given power setting there will be two speeds available (ie: the two
points on the curve where power available = power required). Being 'on
the step' is when you're flying at the higher of the two speeds.

On a video today I saw a demonstration of how to get 'off the step'.
The scenario was a CX B747-400 simulator with RB211-524H engines. The
aircraft was placed at 40,000' and at a weight which gave a margin of
approximately 30-40kts between the stall and high speed buffet. At a
speed ~ 10kts below the high speed buffet the thrust was reduced,
decellerating in level flight until the onset of the pre-stall buffet.
By this time the aircraft had gone past the lower speed at which level
flight could have been maintained with the initial power setting (ie:
the 'off the step speed'), and was so far up the back side of the
power required curve that full power was needed to maintain level
flight, and stop the IAS from reducing further.

The only solution was to descend, trading a bit of that potential
energy to accelerate the aircraft onto the right side of the drag
curve, and then recapture the initial altitude (if you wanted to test
your luck in coffin corner).

A very interesting demo which certainly highlights one of the major
differences between putting around in a Cessna and high altitude jet
transports.
***end quote***

This would appear to be specific to swept wing airliners only.

My father, who flew PB4Y-1's and -2's told me about the climb above
and dive down to cruising altitude technique which he used for his
long range patrol. The PB4Y-1, called the "Privateer" by the Navy,
was the navalized version of the B-24. Loaded for patrol, it would
have been substantially overgross. The B-24 also had a wing called
the Davis Wing, which had a very narrow cord (high aspect ratio) and
it's likely that it had a narrowly defined best cruise angle of
attack. I think it's possible that if you did not accelerate to the
proper airspeed, you could spend a long time wallowing along behind
the power curve before enough fuel burned off to allow the airplane to
nose down to the proper angle of attack. I agree though that finding
that proper cruise attitude and speed could be achieved by the diving
down method as well as leaving climb power on and throttling back once
the proper speed has been reached, or slightly exceeded. The point is
to exceed it slightly before throttling back, I doubt the airplane
cared which way you managed that.

Corky Scott

When people talk about being "on the step" they are talking about their
being a cruise speed above that which can be obtained by accelerating in
level flight. It is a bunch of BS. You are correct that there are two
speeds achievable at any given power setting, one above L/D max and one
under. There are not TWO speeds above L/D max.

In the case of any airplane, if you have power to climb, you have power to
accelerate. There is no case where you can climb to an altitude and not
accelerate to whatever cruise speed is availible (and there is only one).

Mike
MU-2


"Corky Scott" wrote in message
...
On Sun, 31 Oct 2004 14:05:51 -0800, "Peter Duniho"
wrote:

Bottom line: if there were really something to it, it would be wide-spread
industry and military practice. And yet, all those folks continue to
climb
to their altitude, accelerate to cruise speed and then throttle back to
maintain that speed.

Perhaps there is something to it then, check out this blurb from a 747
discussion group, the subject for this discussion was started by
someone asking about flying on the step:

***Begin quote***
As for flying 'on the step', I believe Jetguy's on the money. For a
given power setting there will be two speeds available (ie: the two
points on the curve where power available = power required). Being 'on
the step' is when you're flying at the higher of the two speeds.

On a video today I saw a demonstration of how to get 'off the step'.
The scenario was a CX B747-400 simulator with RB211-524H engines. The
aircraft was placed at 40,000' and at a weight which gave a margin of
approximately 30-40kts between the stall and high speed buffet. At a
speed ~ 10kts below the high speed buffet the thrust was reduced,
decellerating in level flight until the onset of the pre-stall buffet.
By this time the aircraft had gone past the lower speed at which level
flight could have been maintained with the initial power setting (ie:
the 'off the step speed'), and was so far up the back side of the
power required curve that full power was needed to maintain level
flight, and stop the IAS from reducing further.

The only solution was to descend, trading a bit of that potential
energy to accelerate the aircraft onto the right side of the drag
curve, and then recapture the initial altitude (if you wanted to test
your luck in coffin corner).

A very interesting demo which certainly highlights one of the major
differences between putting around in a Cessna and high altitude jet
transports.
***end quote***

This would appear to be specific to swept wing airliners only.

My father, who flew PB4Y-1's and -2's told me about the climb above
and dive down to cruising altitude technique which he used for his
long range patrol. The PB4Y-1, called the "Privateer" by the Navy,
was the navalized version of the B-24. Loaded for patrol, it would
have been substantially overgross. The B-24 also had a wing called
the Davis Wing, which had a very narrow cord (high aspect ratio) and
it's likely that it had a narrowly defined best cruise angle of
attack. I think it's possible that if you did not accelerate to the
proper airspeed, you could spend a long time wallowing along behind
the power curve before enough fuel burned off to allow the airplane to
nose down to the proper angle of attack. I agree though that finding
that proper cruise attitude and speed could be achieved by the diving
down method as well as leaving climb power on and throttling back once
the proper speed has been reached, or slightly exceeded. The point is
to exceed it slightly before throttling back, I doubt the airplane
cared which way you managed that.

Corky Scott

In article ,
Corky Scott wrote:


My father, who flew PB4Y-1's and -2's told me about the climb above
and dive down to cruising altitude technique which he used for his
long range patrol. The PB4Y-1, called the "Privateer" by the Navy,
was the navalized version of the B-24. Loaded for patrol, it would
have been substantially overgross. The B-24 also had a wing called
the Davis Wing, which had a very narrow cord (high aspect ratio) and
it's likely that it had a narrowly defined best cruise angle of
attack. I think it's possible that if you did not accelerate to the
proper airspeed, you could spend a long time wallowing along behind
the power curve before enough fuel burned off to allow the airplane to
nose down to the proper angle of attack. I agree though that finding
that proper cruise attitude and speed could be achieved by the diving
down method as well as leaving climb power on and throttling back once
the proper speed has been reached, or slightly exceeded. The point is
to exceed it slightly before throttling back, I doubt the airplane
cared which way you managed that.


I flew a B-24 for a couple of years. We rarely flew at gross, and
certainly never reached the weights the airplanes were operated at
during the war.

If you didn't either climb above and dive down or leave the power up to
accelerate to cruise speed it would make about a 10-15 mph difference in
speed. The method we prefered and used was to climb above the desired
altitude and dive back down. This was quicker than using power to
accelerate.

A pilot that was ham fisted in pitch could bleed off the speed at cruise
and end up on the low end.

--
Dale L. Falk

There is nothing - absolutely nothing - half so much worth doing
as simply messing around with airplanes.

http://home.gci.net/~sncdfalk/flying.html

"Dale" wrote in message
...
If you didn't either climb above and dive down or
=== leave the power up to accelerate to cruise speed ===
it would make about a 10-15 mph difference in
speed.

[emphasis mine] True...that's what's already been said. Though, in truth,
if you you simply set cruise power, you would eventually accelerate to the
desired cruise speed. It would just take a lot longer.

The method we prefered and used was to climb above the desired
altitude and dive back down. This was quicker than using power to
accelerate.

No, it wasn't. Basic thermodynamics (conservation of energy) dispute that
claim. The time you spent climbing could have been spend accelerating at
climb power, and in the end you'd reach your cruise speed at practically the
same time either way.

A pilot that was ham fisted in pitch could bleed off the speed at cruise
and end up on the low end.

He'd have to be pretty ham fisted to drop from cruise speed all the way down
below best L/D to the other equilibrium speed for the power setting. A
pilot that ham-fisted shouldn't be trusted with a Cessna 150, never mind a
B-24.

Pete

In article ,
"Peter Duniho" wrote:



[emphasis mine] True...that's what's already been said. Though, in truth,
if you you simply set cruise power, you would eventually accelerate to the
desired cruise speed. It would just take a lot longer.

Well, no, you wouldn't. I know this from experience in the airplane.

No, it wasn't. Basic thermodynamics (conservation of energy) dispute that
claim. The time you spent climbing could have been spend accelerating at
climb power, and in the end you'd reach your cruise speed at practically the
same time either way.

Sure worked quicker for us. We tried both methods.

He'd have to be pretty ham fisted to drop from cruise speed all the way down
below best L/D to the other equilibrium speed for the power setting. A
pilot that ham-fisted shouldn't be trusted with a Cessna 150, never mind a
B-24.

It's very easy to do in the B-24, you don't have to be a bad pilot, just
not used to the quirks of the Liberator.

I'm speaking from experience flying the airplane. How much time do you
have in a B-24?

--
Dale L. Falk

There is nothing - absolutely nothing - half so much worth doing
as simply messing around with airplanes.

http://home.gci.net/~sncdfalk/flying.html

"Corky Scott" wrote in message
...
about flying on the step:

***Begin quote***
As for flying 'on the step', I believe Jetguy's on the money. For a
given power setting there will be two speeds available (ie: the two
points on the curve where power available = power required). Being 'on
the step' is when you're flying at the higher of the two speeds.

Mmm? As opposed to flying on the back of the power curve??

Paul

Peter Duniho wrote:



You might as well have asked about "low wing or high wing".

Marvel Mystery Oil similarly makes people lose their minds.

Okay, does high wing or low wing airplanes fly better on the step?

hiding under desk
"Peter Duniho" wrote in message
...
" wrote in message
hlink.net...
I'm reading "Fate is the Hunter" and just read something interesting.
Gann
states that they would climb to 100 feet above their cruising altitude
and
then descend the 100 feet back down. He called this "flying on the
step."
He claims that it bought them a few more knots of airspeed.

Has anyone heard of this? Is it normal practice? Or is it one of those
practices that have been disproven?

You might as well have asked about "low wing or high wing".

Many people, including those who otherwise have great heads on their
shoulders, will swear up and down that "flying on the step" is a real and
useful practice. Many others will just as vehemently point out that
there's
no aerodynamic basis for the claim, and that basic physics argues against
it.

Peter Garrison wrote a decent article on the topic several years back, and
it's come up here every now and then over the years as well. Google
Groups
can help fill you in on past discussions.

Bottom line: if there were really something to it, it would be wide-spread
industry and military practice. And yet, all those folks continue to
climb
to their altitude, accelerate to cruise speed and then throttle back to
maintain that speed.

I will say this (yeah, I know I already wrote my "bottom line" )...it's
a
great question if for no other reason than it gets people thinking about
what the proper sequence of events for climbing and cruising are, as well
the the whys and wherefors regarding an airplane's speed versus power
relationship.

Pete